Pyrotechnic disseminating composition containing a nitramine fuel



United States Patent Ofiice 3,335,040 PYROTECHNIC DISSEMINATINGCOMPOSITION CONTAINING A NITRAMINE FUEL Earl Thomas Niles, Midland,Mich., assignor to The Dow Chemical Company, lVIidland, Mich., acorporation of Delaware No Drawing. Filed Nov. 21, 1966, Ser. No.595,576 5 Claims. (Cl. 149-76) ABSTRACT OF THE DISCLOSURE The inventionis a novel pyrotechnic disseminating composition employing nitramines asfuel, inorganic oxidizers which readily are combustible at atmosphericpressures as oxidizer and effective quantities of an agent to bedisseminated.

This invention relates to pyrotechnic dissemination and moreparticularly is concerned with disseminating systems based on novelpyrotechnic fuel formulations employing nitramines as fuel.

Pyrotechnic disseminating formulations are widely employed for coloredsmoke production used as a signal or screen, for the distribution ofplant growth regulating agents such as pesticides, fumigants, herbicidesand the like and for the release and distribution of chemicals used inWarfare and law enforcement such as tear gas, psychotomimeticincapacitating agents and the like.

The primary problem in disseminating such signalling and treatingmaterials, hereinafter referred to as agents, by pyrotechnic means is inproviding a combustible mixture evolving large quantities of gaseouscombustion products which burns at a sufliciently low temperature suchthat the agent being disseminated is not detrimentally degraded ordestroyed. In general, such compositions should provide large volumes ofgaseous combustion products while undergoing complete burning at a lowburning pressure, e.g. a maximum of about two atmospheres, and a maximumburing temperature of about 800 C. and preferably from about 300 toabout 600 C. It is another criterium of operation that the agent to bedisseminated must be compatible with the pyrotechnic composition toassure reliability of burning after storage as well as storageabilitywithout mix degradation.

Heretofore, pyrotechnic dissemination of smoke dyes, herbicides,chemical warfare materials, tear gas and other like agents has beencarried out using compositions wherein substantial amounts of the agentto be disseminated are mixed with cool burning fuel-oxidizercombinations which provide copious quantities of water vapor and carbondioxide as the principal gaseous exhaust products. In theseformulations, many times undesirable high percentages of the agent arelost through degradation during the combustion dissemination process.

Empirically, it has been found that a mixture of carbohydrates or sulfurwith potassium chlorate in the presence of minor amounts of certainadditives, e.g. sodium bicarbonate with sulfur or kaolin with sugar, canbe used as a pyrotechnic system for dissemination of colored smoke andchemical warfare agents. These systems can be classified as cool-burningonly because of the flame quenching additives employed therein.Polyvinyl acetate in dilute solutions has been used with theseconventional pyrotechnic compositions to increase their physicalstrength and ease of consolidation. Such solutions reduce the amount ofpressure needed to compact the formulations into a grain. This is ofinterest especially with those formulations containing sulfur ascompaction of such formulations at high pressure is hazardous in thatthese 3,335,040- Patented Aug. 8, 1967 compositions during fabricationare prone to ignition. Even when partially compacted, the resultingdeflagration borders on detonation with respect to velocity. Oil, as adiluent, has been used to moisten and reduce friction sensitivity insuch mixtures. This material, however, undesirably degrades thecomposition from the standpoint of efliciency of dissemination.

Dissemination of agents of the type set forth herein also has beenrealized using pyrochemical gas producers as the high volume gas source.To illustrate, self-sustained gas producing reactions as realized by therelatively low temperature catalytic decomposition of ammonium nitrate,guanidine nitrate and nitrogu-anidine utilizing chromates anddichromates as catalysts have been used to disperse benzenehexachloride, DDT and other pesticides. These formulations suffer fromthe disadvantage that they exhibit relatively low efficiency ofdissemination and are not universally applicable.

It is a principal object of the present invention to provide a novelpyrotechnic composition for dissemination of smoke dyes, pesticides,chemical warfare and the like agents.

It is also an object of the present invention to provide a pyrotechnicformulation which is safe to handle during mixing and other productionoperations when in admixture with an agent to be disseminated.

It is a further object of the present invention to provide a pyrotechnicformulation containing an agent to be disseminated wherein the resultantcomposition remains stable under prolonged storage even at relativelyelevated temperatures of 60 C. or more and which gives high efficienciesof gaseous combustion production and agent dissemination upon use.

It is another object of the present invention to provide a pyrotechniccomposition suitable for use with a wide variety of agents ordinarilydispersed by pyrotechnic dissemination.

It is also an object of the present invention to provide a cool-burningpyrotechnic composition for dissemination of agents which requires nocoolant additives.

These and other objects and advantages readily will become apparent fromthe detailed description of the invention presented hereinafter.

The present invention comprises a pyrotechnic disseminating compositionemploying nitramines as fuel, inorganic oxidizers which readily arecombustible at atmospheric pressures as oxidizer and effectivequantities of an agent to be disseminated.

More particularly, the present invention comprises from about 17 toabout 40 weight percent of 3-amino-1- nitroguanidine,ethylenedinitramine or dinitroethyleneurea, from about 7.5 to about 55weight percent of an alkali metal or ammonium chlorate or perchloratesuch as, for example, sodium chlorate (NaClO potassium chlorate (KClO orammonium perchlorate (NH ClO and balance, agent to be disseminated.

A preferred embodiment of the present invention comprises from about 25to about 32.5 weight percent of 3- amino-1-nitroguanidine, from about 12to about 17 weight percent potassium chlorate, and balance agent to bedisseminated.

These formulations exhibit a satisfactory burning rate, are cool burningand develop copious quantities of neutral (i.e. substantiallynon-reactive with agent) gaseous combustion products to provide goodagent dissemination. If desired, however, optionally up to about 5percent by weight or more, ordinarily from about 1 to about 5 weightpercent, and preferably about 1 Weight percent of a combustion catalyst,e.g. chromates, copper salts, platinum, rhodium or iridium metals,ferrocene, metal chromites, ferric oxide and the like can beincorporated into the formulation. Alkali metal chromates, e.g.potassium chromate (K CrO and copper halides, e.g. copper chloride,copper chromite and ferric oxide (F6203) have been found to beparticularly suitable catalysts. With the catalysts, sustainedcombustion is realized at stoichiometric or fuel rich fuel-oxidizerproportions. If the catalyst is not employed, the composition usuallymust be oxidizer rich to obtain sustained combustion. In some instances,this can lead to undesirable agent degradation during the combustiondissemination process. Additionally, the catalyst provides increasedburning rates and increased gaseous combustion product yield andefiiciency of agent dissemination.

Agents for dissemination which can be incorporated into the formulationinclude for example organic dyes such as methylaminoanthraquinone (MAAQ)used for the production of colored smoke, tear gas agents,incapacitating agents which are psychotomimetics, her-bicides,fungicides, pesticides and the like.

By effective quantities of such agents is meant those amounts whereby apredetermined level of treatment or activity is realized as isunderstood by one skilled in the art of pyrotechnic dissemination.

The formulations can be fabricated into compacts or grains usingtechniques and procedures commonly em ployed in the art. Blends usuallyare made by mixing the components, placing the resulting substantiallyhomogeneous mix into a container, compacting the mix in the containerand contacting the so-compacted formulation with an ignition system andigniter.

First Fire and a No. 56 Squib igniter was inserted into the can throughthis opening and placed in contact with the dissemination formulation.

The so-pressed end burning grain was ignited and burningcharacteristics, including ease of ignition, burning time, combustiontemperature and pressure were recorded. Additionally the aerosol yield,

!gent in Aerosol Form X 100 (Aerosol yield Total Weight Composition and. Agent in Aerosol Form X 100 (Emmemy Agent in Composition also weremeasured.

The results of these studies are summarized in Tables I and II. To aidin the ease of understanding and ready presentation of the results, theoperable and optimum com-position ranges are shown in Table I. Table IIsummarizes the burning characteristics exhibited by the compositions ofcorresponding number in Table I.

TABLE I Fuel KO 0 l soxidizer, KzCX'O4 Catalyst, MAAQ Agent Comp. Partsby Weight Partsb We ht P No. Parts by Weight y g ms by Weght ComponentOperable Optimum Operable Optimum Operable Optimum Operable I OptimumMin. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max.Min. Max.

1a B-amino-l-nitroguanidine. 17 lb 2a D1n1troethyleneurea... 29 2b 0 3Ethylenedinitramine 28 1 System not optimized.

TABLE IIB URNING CHARACTERISTICS C Tlgilrning qOombusttion Cti mbustionClfinltitin Axgflifiol Efficiency,

omp. e, sec. empera ure, ressure arac erie Percent Im act S a k No.(range) 0. (range) (range) istics Percent (range) p p r Fnctmn x51General (range) 9-15 270-500 M-G G 3641 63-74 G 10-11 -400 G G 404173-74 G g g g g 30-33 380???) g-G L-G 25 50 G G G G G N G G 26-32350-500 MG L-G 25-30 52-60 G G g g 8 1 Formulation compatibility afterlong term (9-12 weeks) storage at about 70 C P=Poor, L=Low, M=Mediu.m,G= Good (based on Poor as minimal acceptable performance for use inagent disseminating).

Internal burning grains are prepared by pressing or compacting the blendaround a mandrel of predetermined shape and size.

The present novel pyrotechnic disseminating formulations offer theunexpected advantage of safety during mixing with agents that aresomewhat hazardous to handle in the presence of sulfur. Also, theyprovide unexpectedly high stability during storage as well as higherefliciency of dissemination when compared with formulations based onconventional pyrotechnic systems.

The following example will serve to further illustrate the presentinvention but is not meant to limit it thereto.

Example.For aerosol evaluation, a number of formulations were preparedby mixing a nitramine fuel and potassium chromate catalyst,incorporating MAAQ smoke the like, as disclosed herein can be utilizedin these compositions.

Various modifications can be made in the present invention withoutdeparting from the spirit or scope thereof for it is understood that Ilimit myself only as defined in the appended claims.

I claim:

1. A pyrotechnic disseminating formulation comprising (a) from about 17to about 40 weight percent of a nitramine as a fuel member,

(b) from about 7.5 to about 55 weight percent of a member selected fromthe group consisting of alkali metal and ammonium chlorates andperchlorates as oxidizer, and

(c) balance an effective amount of agent selected from the groupconsisting of organic dyes, chemical warfare agents, incapacitatingagents, and plant growth regulants to be disseminated.

2. The composition as defined in claim 1 and including up to about 5weight percent of a combustion catalyst.

3. The composition as defined in claim 1 wherein the fuel member isselected from the group consisting of 3- amino-l-nitroguanidine,ethylenedinitramine and dinitroethyleneu-rea and said oxidizer ispotassium chlorate.

4. The composition as defined in claim 3 and including from about 1 toabout 5 weight percent of potassium chromate combustion catalyst.

5. The composition as defined in claim 1 wherein the fuel member is3-amino-1-nitroguanidine, said fuel member ranging from about 25 toabout 32.5 weight percent, the oxidizer is potassium chlorate, saidoxidizer ranging from about 12 to about 17 weight percent and includingabout 1 weight percent potassium chromate catalyst.

References Cited 7 UNITED STATES PATENTS 2,557,814 6/1951 Dinsdale et al14985 X 2,557,815 6/1951 Wheelwright et al. 149-85 X 2,707,695 5/ 1955Courtier 14992 X 3,042,580 7/ 1962 Jacobi 149-'61 X CARL D. QUARFORTH,Primary Examiner.

S. J. LECHERT, JR., Assistant Examiner.

1. A PYROTECHNIC DISSEMINATING FORMULATION COMPRISING (A) FROM ABOUT 17TO ABOUT 40 WEIGHT PERCENT OF A NITRAMINE AS A FUEL MEMBER, (B) FROMABOUT 7.5 TO ABOUT 55 WEIGHT PERCENT OF A MEMBER SELECTED FROM THE GROUPCONSISTING OF ALKALI METAL AND AMMONIUM CHLORATES AND PERCHLORATES ASOXIDIZER, AND (C) BALANCE AN EFFECTIVE AMOUNT OF AGENT SELECTED FROM THEGROUP CONSISTING OF ORGANIC DYES, CHEMICAL WARFARE AGENTS,INCAPACITATING AGENTS, AND PLANT GROWTH REGULANTS TO BE DISSEMINATED.